/***************************************************
* sierpin.cc: Creates Sierpinsky Carpet
*
* written by: Paul M Eugenio
*             Department of Physics
*             Florida State University
****************************************************/
#include <iostream>
#include <stdlib.h>

using namespace std;

int main() {

  double r;           // random number
  double x =0.0;      // x coordinate
  double y =0;        // y coordinate
  double max = 10e3;  // max number of points 

  //
  // simple structure to contain
  // the triangle vertices coordinates
  //
  struct vert_s { 
    double x; 
    double y;
  }V[3];
  
  // simple equilaterial triangle
  V[0].x=0;
  V[0].y=0;
  V[1].x=1;
  V[1].y=0;
  V[2].x=0.5;
  V[2].y=1;

  //seed48()
  int n;
  for (int i=0; i<max; i++) {
    r = drand48();  // get a random number r = [0,1)

    //
    // choose a random point and move half-way
    // to that point.
    n = int(3*r); 
    x = (x+V[n].x)/2.0; 
    y = (y+V[n].y)/2.0;

    // Note: n=0 if r <= 1/3
    //       n=1 if r > 1/3 && r <= 2/3
    //       n=2 if r > 2/3 && r < 1
    
    // print point to the standard output
    cout << x << " " << y << endl;
  }
}